Installation of communication cables, such as fiber optic cables, routinely involves burying the cable underground. For example, communication companies bury cables underground for protection, safety, and to meet local codes. Locating such buried cables years after installation is often problematic. Without knowing the precise location of the buried cable, servicemen may inadvertently sever the cable when installing or servicing an adjacent communication cable, utility line, sewer, waterline, gas pipe, or electrical cable. To minimize the aforementioned drawbacks, utility companies typically rely on electromagnetic signaling to locate buried cables.
Currently, buried fiber optic cables are located using electromagnetic signals generated from wires in ducts radiating an electromagnetic signal or by incorporating an electrically conductive wire in the cable construction for carrying a detectable electromagnetic signal. A conventional method for incorporating a conductor into a stranded tube fiber optic cable is to place the conductor in a position usually reserved for one of the tubes. However, this method has several drawbacks. One drawback is that the conductor becomes an integral component of the core, making access to the conductor difficult, often requiring a technician to expose the entire cable core. Another drawback is that the overall optical fiber density of the cable design is reduced.
Yet another drawback to incorporating a wire conductor into a stranded tube fiber optic cable is that the conductor may create an imbalance of contractive forces in the cable, attenuating or distorting the optical fibers' signals at low temperatures. Addressing such forces with conventional technologies involves incorporating cumbersome changes to a standard cable design to negate the unbalanced, contractive forces. Such changes may detrimentally increase cable diameter, for example causing issues with innerduct installation.
Accordingly, to address these representative deficiencies in the art, an improved capability is needed for detecting a buried fiber optic cable. Another need exists for an apparatus that can be disposed in a fiber optic cable to facilitate locating the cable while maintaining signal balance in the cable and desirable diameter profile. Yet another need exists for an apparatus that can be disposed in a fiber optic cable to facilitate locating the cable and that can be accessed easily without exposing the cable core or while keeping the cable core intact.
A capability addressing one or more of the aforementioned needs, or some related need in the art, would support increased usage of buried fiber optic cables and would reduce service disruption associated with inadvertently severed cables.